A peptide (NH2-Ser-Glu-Lys-Ser-Glu-Glu-Ile-Asn-Glu-Lys-Gly-Lys) from the N-terminal sequence of staphylococcal enterotoxin A (SEA) was synthesized and conjugated to bovine serum albumin (BSA). When injected into rabbits, this conjugate induced antibodies which reacted with the native SEA molecule. These antibodies did not cross-react with other enterotoxins. However, the obtained anti-peptide antibodies were less efficient in detecting SEA than antibodies raised to the whole molecule.